Gnomidolon hamatum Linsley, 1935

García, Kimberly, 2019, A new species of Gnomidolon Thomson, 1864 and taxonomic and geographical notes on Hexoplonini (Coleoptera, Cerambycidae) from Colombia, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 59, pp. 1-7 : 5-6

Gnomidolon hamatum Linsley, 1935 ( Fig. 2 )

Redescription: Male: Integument yellow, darker in some areas. Head and prothorax brown. Ventral habitus dark

brown. Each elytron with a semicircular dark brown band on anterior half, beginning near base and reaching middle of elytron.

Head: Frons tumid on area close to clypeus; tumid area glabrous surrounded by coarse punctation. Longitudinal sulcus evident on frons and area between antennal tubercles, with dense, coarse punctation and few decumbent setae. Area between antennal tubercles densely, coarsely punctate. Vertex with shallow depression; sparsely and coarsely punctate; with a few long, erect setae. Area behind eye lobes with long erect setae. Submentum coarsely striate; with short and long erect setae. Antennal tubercles microsculptured, elevated, rounded at apex. Distance between upper eyes lobes 2.3 times width of upper lobe. Antennae twice elytral length, reaching elytral apex at antennomere IX. Scape cylindrical; scape and pedicel with short decumbent setae. Antennomere III distinctly elongated, 1.7 times length of antennomere IV. Antennomeres IV-X subequal in length, with yellow short decumbent setae; III-IV with long erect setae at inner face, and V-X with long erect setae at apex. Antennomere III-V bicarinate. Antennal formula (ratio) based on length of antennomere III: scape = 0.55; pedicel = 0.11; IV = 0.58; V = 0.64; VI = 0.66; VII = 0.63; VIII = 0.57; IX = 0.54; X = 0.54; XI = 0.73.

Thorax: Prothorax cylindrical,with parallel sides;1.5 times longer than wide. Pronotal disk with 2 median smooth gibbosities. Surface of pronotum with dense, fine punctation and a few long, erect setae, except for gibbosities. Lateral sides of prothorax with same sculpture as pronotum. Prosternum glabrous on anterior margin, slightly striated with a transversal, fine line of short decumbent setae; remaining area with dense, fine sexual punctation. Prosternal process pubescent and narrow, divergent toward apex, apex truncate, width at narrowest point about 0.2 times of procoxal cavity width. Mesoventrite pubescent, tumid in area close to mesoventral process. Mesoventral process sparsely pubescent,emarginated on apex, width at narrowest point about half of mesocoxal cavity width.Mesanepisternum and mesepimeron densely pubescent. Metaventrite densely pubescent, except centrally with a few short decumbent setae interspersed with long erect setae. Metanepisternum pubescent. Scutellum sparsely pubescent, denser on apex; rounded at apex. Elytra densely and coarsely punctate on anterior half, finer toward apex; with long, erect setae aligned in three longitudinal rows, denser and irregularly aligned toward apex; each elytron with one oblique dark-brown band. Apex emarginated with long spine at outer angle, 0.8 times length of pedicel; and small sutural projection.

Legs: Femora cylindrical (mainly metafemora); with long, erect setae on inner face; apex of mesofemora with short spine at inner side; apex of metafemora with short spine at inner and outer side. Meso- and metatibiae carinate; with sparse long erect setae, denser toward apex. Metatarsomere I subequal in length than II-III together.

Abdomen: Ventrites densely pubescent, with a few long erect setae; ventrite I longer than II-III together; apex of ventrite V truncate.

Measurements (in mm): Male, total length: 12.6, prothorax length: 2.7, largest prothoracic width: 1.9, elytral length: 8.3, humeral width: 2.6.

Material examined: COLOMBIA, Atlántico: Usiacurí (Reserva Campesina La Montaña, 260 m, 10°46.0’2.6”N, 75°00.2’34.0”W, tropical dry forest), 1 male, 12-13.V.2018, García,K.col.,white light trap MPUJ_ENT 0064763 ( MPUJ).

Remarks: Gnomidolon hamatum was described by Linsley (1935) based on a single female specimen from Panama. Later, Martins (1967) redescribed the female examining the holotype. The species was included in several catalogues, expanding its distribution to Costa Rica ( Swift et al., 2010). Herein, the male is described and illustrated for the first time, and sexual dimorphism in the punctation on prosternum is observed ( Fig. 2E ), as well as differences in the pilosity on prosternum between females and males ( Fig. 2F ). This sexual dimorphism in the pronotal pilosity is also present in G. guianense , howev- er males of this species present the same punctation as females. The male of G. hamatum also differs from the female ( Figs. 2 F-2H) in lacking the posterior dark brown spot with triangular shape ( Fig. 2G ). As the material examined is from Colombia, the geographical distribution of the species is expanded to South America.

Figures

Figure 2. Gnomidolonhamatum Linsley,1935.(A-E) male:(A) dorsal view;(B)ventral view;(C) lateral view;(D) frontal view;(E)detail of prosternum.(F-H) female: (F) detail of prosternum;(G) dorsal view;(H) ventral view.